In message <u682vg$380e6$1@dont-email.me>, at 21:33:36 on Mon, 12 Jun
2023, Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> remarked:
>Roland Perry <roland@perry.uk> wrote:
>> In message <u65i3s$2qtc6$1@dont-email.me>, at 22:33:32 on Sun, 11 Jun
>> 2023, Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> remarked:
>>> Roland Perry <roland@perry.uk> wrote:
>>>> In message <u62mq7$2dlnf$1@dont-email.me>, at 20:35:19 on Sat, 10 Jun
>>>> 2023, Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> remarked:
>>>>> Roland Perry <roland@perry.uk> wrote:
>>>>>>
>>>>>> My network at home comes "out of the box" with IPv4 and IPv6 inside the
>>>>>> house, but only IPv4 to the wider Internet.
>>>>>
>>>>> If the home network is a single subnet then having IPv6 locally is
>>>>>the same
>>>>> as any other network;
>>>>
>>>> I can't parse that. Former home networks of mine only had IPv4 locally.
>>>
>>> Any systems within a single LAN can use IPv6 without any router or network
>>> server (DHCP or whatever) needed. It just works. They’re probably doing
>>> it without you knowing.
>>
>> Except I do know, I've looked at the configs!
>
>OK, so you’ll know whether your systems are talking to each other using
>FE80: addresses, and if so then there’s no need for the router to have
>anything to do with them.
>
>>> By default most home routers on the home side simply bridge the
>>> wireless and wired connections together so they’re one LAN.
>>
>> I've got a guest wifi (which can only access the outside world) as well
>> as the wifi for residents/applicances.
>
>OK, so if your guests’ devices can access each other (some wifi systems
>prevent that) they can also talk IPv6 to each other but not to the outside
>world because your router doesn’t have IPv6 on the uplink.

Yes, as far as I can tell there's IPv6 all round the inside, but none
outside.

>>>>> if you’ve got a router which has multiple interfaces on house LANs
>>>>> running IPv6 but an IPv4 only uplink I’d be interested in knowing
>>>>> what it is and who supplied it.
>>>>
>>>> I think it's a Technicolor TG588, and was supplied by my ISP.
>>>
>>> Thanks. The two guides I’ve found suggest that there’s the
>>>option to route
>>> IPv6 on the WAN side, but I’ve not found anything other than a simple
>>> switch which it’s recommended to leave in the default off position.
>>
>> I suspect the backhaul isn't IPv6 enabled. Despite all the 2010-era
>> shroud waving, IPv4 seems to still be in business.
>
>Sky are supposed to have enabled IPv6 everywhere some years ago; someone I
>knew was the network architect who designed and implemented the system.

>BT were supposed to be doing so but I’ve not seen any evidence.

If I were to get BT's Full-Fibre (which I probably wouldn't for lots of
other reasons) I would expect to have IPv6 to the outside world. Not
sure if I'd expect at least one public IPV4 address too - if not then
it's still a bit early days to be running servers at home.

Last I heard (which was admittedly a few years back) is that for ADSL
customers they were eking out their IPv4 space by deploying
carrier-grade NAT to domestic customers.

>> But I'm sure I only have one IPv4 public address. Back in the day you
>> could get sixteen with Demon.
>
>You should get 256 *subnets* with IPv6.

There was a big debate about minimum IPv6 allocation quite a while back
now. I'm not up to date with the current guidelines. What I do know is
that people who talk about IPv6 having "quadrillions of addresses
available" is that they include all that empty space that's going to be
unused at every customer site.
--
Roland Perry